I have a 03 F150, 5.4 Super crew with 136K miles on it. I've noticed in the last year that it has a slight rough idle but nothing bad enough for me to have it checked out. Well yesterday the service engine light came on so I took it to the auto parts store to have it read. The code came back as a EGR Valve. I know nothing about these things. Can anyone give me any info and what I need to do and will it cost me a lot? Does this possibly cause the rough idle I've been experiencing? Thank you.

 

The rough idle is probably either the idle air control, or a bad fuel pressure regulator. The EGER passes exhaust gas back into the combustion chamber to "reburn it". But since it's inert it won't burn, it's already burned. But what it does is cool the combustion.thus reducing emissions. It is vacuum operated. Seldom goes bad, but does plug up. You can check it by gently lifting the diaphragm to let exhaust to pass. But be warned, it gets very hot and will burn you. Usually cleaning is all thats required. Un bolt it, take it off, and run crab cleaner through the passages.

 

Usually not too hard to change or real costly. Basically introduces exhaust gasses into the intake to improve combustion efficiency, should be closed at idle. When they stick open causes rough idle.

 

Thanks for the info. I will try cleaning it out and see if that clears the check engine light. Appreciate the help!